there are 3 fee in mycelium, 0.2 mBTC ; 0.1 mBTC ; 0.01 mBTC
I haven't checked made any tests. I only use Mycelium for sending BTC from a private key.
Do you mean we can choose any of these amounts as fee per 1000 bytes?
you probably got a high fee because you tried to spend a low input
Nope.
or one from a sendmany(exchanges and the sort)
Nope.
Mycelium gave me fees higher than it should be. Size were low, so the fee should be too. Also I am spending from a private key not from address in wallet.